This invention relates generally to semiconductor packaging.
Semiconductor packages typically are connected to a motherboard via the use of solder balls. Such packages should survive shock and vibration as may occur during shipping, for example.
The solder balls are typically soldered to the package leads by formation of intermetallic compounds (IMC's). These IMC's are typically very brittle and can undergo fracture easily under shock and vibration conditions. This is especially true in the case of lead free solders and lead free packaging technologies since both the lead free solders and the IMC's formed by the lead free solders are typically stiffer and more brittle than current leaded solders.
Further, with the need to miniaturize devices and increase packing density, the size and pitch of the solder balls is continuing to decrease. Smaller solder balls lead to a higher risk for shock and vibration related failures in the solder joint.